FYI, yes you can sell pumice, it has uses:
Because the original joke and your comment were both premised on how we valuing things / create valuations for things, and at its core, this is was why the field of environmental economics exists.
Prior to environmental economics, we had capitalists saying non-market environmental goods (e.g. the existence/conservation of whales, conserved lands / national parks, etc) are not worth anything bc they don't have a market value. And on the other extreme you had environmentalists who were claiming that these goods are priceless / immeasurable / infinite value.
The chasm between 0 and infinite didn't leave much room for these two sides to compromise. And so the field of non-market valuation was born. It attempts to value non-market goods by calculating the positive and negative externalities of these goods. Thus, in the case of the Great Barrier Reef, we could attempt to calculate how much effect this pumice raft would have on the health of the reef and then we would calculate how much value the reef provides through its biodiversity.
Even if we are extremely underestimating the value, a lower bound estimate is still better than is being valued at 0.
And then we can estimate the internalized market value of this good. i.e. what would the market pay given current market prices for pumice? And what is the cost of harvesting this pumice versus other pumice. Because other pumice doesn't have these potential environmental benefits. It simply sits on the ground or underground close to the surface.
So if the costs of these 2 sources of pumice are close but the benefits of the sea raft pumice is much higher, than the government should put a Pigouvian tax on the raft pumice to discourage its harvesting (or simply ban such harvesting).
But I would wager this is all a fruitless conversation because I bet the cost of harvesting the sea raft pumice is much higher than the cost of harvesting land pumice.
Pumice Prices (closer to retail):
- $7-18 per pound for cement mix
- $2-9 per stone for scrubbing, cleaning, and exfoliating
- $8-16 per pound for powder use in makeup and exfoliating body scrubs
Given that pumice is mined via open pit mining, it is very cheap, economical/efficient, and environmentally friendly:
>The mining of pumice is an environmentally friendly process compared with other mining methods because the igneous rock is deposited on the surface of the earth in loose aggregate form. The material is mined by open pit methods. Soils are removed by machinery in order to obtain more pure quality pumice. Scalping screens are used to filter impure surficial pumice of organic soils and unwanted rocks. Blasting is not necessary because the material is unconsolidated, therefore only simple machinery is used such as bulldozers and power shovels. Different sizes of pumice are needed for specific uses therefore crushers are used to achieve desired grades ranging from lump, coarse, intermediate, fine and extra fine.
I don't think harvesting from the ocean would be cheaper than using simple bulldozers to fill trucks. Given that it then needs to be dry, the energy costs of ocean pumice would be much higher (even if the initial harvesting could be comparable in cost).
Thus, no intervention is needed because no one would even think about harvesting this pumice...
 A simple example is using the travel cost method from non-market valuation to value a national park. Even though parks are virtually free (visitors pay a nominal fee), we can add up all the money someone spends to fly their family to Yellowstone and then rent a vehicle and pay for hotels and say all that money spent is a lower bound
Additionally, the minerals will dissolve in more acidic water.
The problems of coral reefs are caused by the water becoming hotter and more acidic. I fail to see how pumice makes the water cooler and more basic.
GBR is off Australia, we can drop that. "Toward" adds little. Rearrange:
"Giant Floating Pumice Raft Could Help Replenish Great Barrier Reef"
Since "raft" implies "floating" and "giant" is a largely superfluous conditional (anything that might help the GBR would have to be substantive), you could drop those for a length of 52 characters.
Headline writing / editing is an art.
I had the same problem with reducing the title. In the end I decided to leave mention of the Great Barrier Reef out of the title entirely. But that also perhaps made it less likely to receive upvotes.
Why do people let crazy ideas like this get media time?
"Giant Hamburger Headed Towards Reef Could Replenish It".
Like the thing about robot fish saving the reef, or a garbage collecting boat clearing the plastic from the oceans.
May as well be writing about how aliens will be coming to save The Reef.
It enables climate change deniers.
Just because this hasn't happened in the 150 years we've been semi-accurately recording things in the south Pacific doesn't mean it's not a common occurrence.
Volcanic ejecta is extremely mineral rich, and when combined with decomposing organics makes some of the best, most fertile soil you can get.
Bryan said the raft will be the temporary home for billions of marine organisms. Marine life including barnacles, corals, crabs, snails and worms will tag along as it travels toward Australia and become a "potential mechanism for restocking the Great Barrier Reef".
This was then more widely reported as "Scientists say..."
It appears Bryan is a geologist specializing in volcanology who has expertise in pumice rafts, but not in marine biology. One would have hoped he would know better than to make such statements to the media.
But yes, it may be a case of over-positivism as I call it, being so optimistic that a natural disaster is viewed from the prism of - that's good news. More so when one natural disaster can be perceived as a solution to another disaster, albeit one in which we played a part. Heck, it's even possible to say that this volcano underwater would not of erupted had we not changed the climate.
But however we look at it, it would be nice to see some more balanced perspectives without the over-positive spin. Will this heat up the ocean in the vicinity due to it absorbing more heat, will it starved of oxygen as it blocks photosynthesis in the area it travels. Those tangents of thought get overlooked, yet have just as much plausibility than latching onto how this is the saviour of the coral reef.
But one question I have - pumice volcanic rock, what gas is trapped in that rock?
Or how about "residents advised to evacuate, as hurricane could strike town"
Very few things are guaranteed, and I for one would like to be forewarned about things.